Technical Field
The present invention relates to manufacturing a plastic container and for filling it with a fill product, for example for manufacturing and filling blow molded or stretch blow molded polyethylene terephthalate (PET) bottles.
Related Art
Blow molding machines and stretch blow molding machines are known from the state of the art. On these machines, plastic containers, for example PET plastic bottles, are manufactured. For this purpose, so-called preforms are first heated in an oven and then, in the actual blow molding machine or stretch blow molding machine, introduced into a blow mold, which has an inner contour corresponding to the shape of the PET plastic bottle that is to be manufactured. These preforms are then inflated into finished plastic bottles by means of pressurization with a blowing medium. The contour of the container is impressed on it by the blowing pressure, which presses the material of the preform onto the inner wall of the cavity of the blow mold.
In the stretch blow molding method, prior to the main pressurization of the preform, or rather the interior of the preform, with a blowing medium, the preform is pre-stretched mechanically by means of a stretching rod, and at the same time the preform is pre-inflated. After it is pre-inflated the preform is pressurized with the blowing medium such that the preform is pressed onto the inner wall of the cavity of the blow mold. The blow mold is then opened, so that the fully blow molded or stretch blow molded PET plastic bottle can then be removed and conveyed to its further processing.
The blow mold usually has at least one separate blow mold base and two blow mold halves, which can be moved apart such as to allow the finished PET plastic container to be removed without problems. At the same time, a preform can also be introduced into the blow mold that has been opened in this manner.
Various different designs are possible for the blow molding machines. In particular, blow molding machines of the rotary type are known, which have circulating blow molds disposed on a carousel, so that substantially continuous manufacture of plastic bottles can be achieved. Blow molding machines with stationary blow molds are also known, in which a plurality of blow molds are normally disposed one behind the other, or a single blow mold is equipped with a plurality of cavities. In such a blowing device with stationary blow molds, PET plastic bottles can thus be manufactured in cyclic operations, and subsequently conveyed to their further processing.
After being manufactured in the blow molding machine and removed from their respective blow molds, the PET bottles are typically filled in a filler device, in which the containers are retained either at their base or, in the case of PET bottles, at their support ring, and filled by means of a fill product valve, which is known in the art. A wide variety of different filling systems and/or filling elements are known for filling PET plastic bottles, which enable for example free-jet filling, counter-pressure filling, weight filling, vacuum filling or dosing chamber filling, to name only some of the known filling methods.
Prior to the actual filling of the PET bottles, they are commonly rinsed or sterilized, in order to enable them to be filled in a hygienic or sterile manner. It is further known, prior to the actual filling of the containers with the fill product, in particular in the case of fill products that are sensitive to oxygen, to provide a defined gas composition in the containers, preferably a gas composition that is low in oxygen. For this purpose, the containers to be filled are usually subjected to gas flushing, in which an underpressure is first produced in the container, then a flushing gas, for example an inert gas such as CO2 is introduced into the container. The fill product is then filled in this defined gas atmosphere. The flushing procedure can also be carried out repeatedly if an atmosphere particularly low in oxygen is required in the interior.
Methods for manufacturing and filling containers are also known in which the manufacture of the plastic bottles is carried out in a blow molding machine or stretch blow mold machine, and the containers are filled with the applicable fill product while still in the blow molding machine itself. The advantage of this method is that the interior space of each container is virtually sterile after its manufacture, because the preforms for blow molding have already been heated to high temperatures, such as at or above 100° C. When each plastic container is filled immediately after it is manufactured, sterile or at least hygienic filling of the applicable fill product is possible.
For example, from DE 26 57 670 A1 a blow molding and filling head for devices for molding and filling hollow bodies formed from thermoplastic materials is known, in which the molded containers are immediately charged with fill product by means of the blow molding and filling head.
From EP 1 529 620 A1, a filling head is known, in which the inflation of each plastic container is carried out by means of the fill product. Accordingly, the container is fully filled with the fill product immediately when manufacture is completed, so that in this case manufacture and filling take place simultaneously.
In the known methods by which the container is filled while still in the blow molding machine, the filling takes place in conditions of either ambient pressure or overpressure.